On master page(parent page from which we are opening the LOV page), we have the following - Text input fields and one drop-down list.
On LOV page(pop-up page), we have the following Search values - Two text input fields and one drop-down list.

We have used ADF LOV in our project. We have used the Advance Search method to find.
As per the requirement, we have to disable the master page till user didn't find the value on LOV page.

To achieve above, we have set the value in SessionScope on Find Button of LOV page and checking the value on master page.

When we are opening the LOV from master page and after Find if we are clicking the Add New button(custom button) on LOV, it is not refreshing the master page and master page remains in the read-only mode due to this we are not able to update the value. After refreshing the master page it is coming in editable-mode.

Expected result - The master page should come in editable-mode after clicking the Add New button(custom button) on LOV page.
Actual result - The master page is coming in read-only mode after clicking the Add New button(custom button) on LOV page.

I am sorry, this forum can only help you with JHeadstart-specific issues. You are trying to add additional custom functionality which is beyond the scope of this forum.
You will first have to make that work yourself (or ask JDeveloper forum for help), if you then have trouble preserving those customizations when regenerating, this forum can help you again.